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Comparative structural and functional analysis of two octaheme nitrite reductases from closely related T hioalkalivibrio species
Author(s) -
Tikhonova Tamara,
Tikhonov Alexey,
Trofimov Anton,
Polyakov Konstantin,
Boyko Konstantin,
Cherkashin Eugene,
Rakitina Tatiana,
Sorokin Dmitry,
Popov Vladimir
Publication year - 2012
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2012.08811.x
Subject(s) - random hexamer , nitrite reductase , protein data bank , nitrite , structural motif , protein data bank (rcsb pdb) , chemistry , enzyme , stereochemistry , biochemistry , biology , protein structure , organic chemistry , nitrate reductase , nitrate
Octaheme nitrite reductase from the haloalkaliphilic bacterium T hioalkalivibrio paradoxus was isolated and characterized. A comparative structural and functional analysis of two homologous octaheme nitrite reductases from closely related T hioalkalivibrio species was performed. It was shown that both enzymes have similar catalytic properties, owing to high structural similarity. Both enzymes are characterized by specific structural features distinguishing them from pentaheme cytochrome c nitrite reductases, such as the T yr‐ C ys bond in the active site, the hexameric structure resulting in the formation of a void space inside the hexamer, and the product channel that opens into the void interior space of the hexamer. It is suggested that these specific structural features are responsible for the higher nitrite reductase activity, the greater preference for nitrite than for sulfite as a substrate, and the wider p H range of the catalytic activity of octaheme nitrite reductases than of pentaheme homologs. Database Nucleotide sequence data are available in the GenBank database under the accession number HQ665012.1 . Structural data are available in the RCSB Protein Data Bank database under the accession numbers 3SXQ and 3TTBStructured digital abstractTvPaR and TvPaR bind by x-ray crystallography ( View interaction )